http://www.w3.org/TR/SVGMobile12/text.html#TextAlignProperty
There are two problems with this definition. First
# Note that SVG does not require user-agents to support the
# following values for this property: "justify", "inside",
# "outside", <string>, "left", or "right". When an unsupported
# value is encountered it must be treated as the property
# had not been specified.
It should be normatively allowed for the UA to support the
other values of text-align. If the UA also supports CSS then
it's not possible for the values not listed here to be ignored.
Second problem is here:
# The values "start" and "end" are dependent on the writing
# system being used.
#
# * For left to right horizontal (English, French, etc):
# start=left and end=right
# * For right to left horizontal (Hebrew, Arabic, etc):
# start=right and end=left
# * For top to bottom vertical (vertical Chinese, etc):
# start=up and end=down
"writing system being used" is not a good basis for alignment.
What about mixed script text? text-align should be dependent
on SVG's equivalent of the containing block's 'direction'
property. (Which afaict doesn't exist in SVG Tiny, but more on
that problem later.)
Also given "In SVG Tiny 1.2, vertical writing is not supported."
in http://www.w3.org/TR/SVGMobile12/text.html#TextLayout that
last sentence should be removed.
~fantasai